Pressure operated switch



DecQG, 1932. ,1. G. GEwEcKE ET AL 1,890,376

PRESSURE OPERATED SWITCH Filed July 13, 1931 2 Sheets-Sheet l Dec. s, 1932.

J. G. GEwEcKE ET Al.

PRESSURE OPERATED SWITCH Filed July 15. 1931 2 Sheets-Sheet @wao/5.

/Illomey Patented Dec. 6, 1932 UNITED STATES PATENT OFFICE JOSEPH G. GEWECXE, MEL'VIN I. ELLISON, AND WILLIAM H. HENXING, 0F GENEVA,4

` NEBRASKA PRESSURE OPEBATEI) SWITCH Application illed July 18 This invention relates to a low pressure signal for automobile tires, the general object of the invention being to provide means for operating a signal when any one of the four tires of the vehicle becomes partly deflated.

This invention also consists in certam other features of construction and in the combination and arrangement of the several 1o parts to be hereinafter fullydescribed, illustrated in the accompanying drawings and s eciically pointed out in the appended c aim.

In describing the invention in detail, reference will be had to the accompanying drawings, wherein like reference characters denote like or corresponding parts throughout the several views, and in which:

Figure 1 is a fragmentary viewwith parts in section showing the invention applied to a wheel. i

Figure 2 is a longitudinal `sectional view of the pressure switc i Figure 3 is a section on the line 3-3 of 26 Fi ure 2.

igure 4 is a section on the line 4-4 of Fi ure 2.

igure 5 is a diagrammatic view of the circuit.v 1 3o Figure 6 is a section on the line 6-6 of igure 7 is an elevation of the part of the stationary portion of the brake drum.

In these drawings the numeral 1 indicates the stem of the innertube 2 of the tire 3, and the numeral 4 indicates the casin having one end formed with a threaded ho e to receive the reduced end of the casing stem. Within the casin 4 is a member 5 for engaging the valve 6 o the stem to hold the same in open position when the casing is screwed on the stem.

The open end of the inflatable casing 7 formed of rubber or the like, is held against the outer end of the casing 4 by the nut 8 so that air from the tube 2 will enter the casing 7 to expand the same. A washer 9 is fastened to stem 10 which is slidably. arran ed in the non-conducting discs 11 carriedg by a tubular member 12 .which is thread- 1931. Serial No. 550,588.

ed in the inner end of the casing 4 and acts ,as a closure member for the same.

" A` contact ring 13 is carried by one of the non-conducting discs 11 and is engaged by the head 14 on the stem 10 when the member 9 is moved toward the valve stem 1 by the spring 15 which has one end connected with the member 9 and the other end suitably connected with the nut. The contact 13 kis connected by wire 15 to a. cylinder 16 carried by and insulated from a stationary part 17 of the wheel and this cylinder has a carbon block 18 therein which is normall pressed outwardly by spring 19 in the cylinder so that the block will be held in engagement with a ring 20 in the brake drum 21 of the wheel and insulated therefrom by the n0n-conductingring 22. A conductor 23 is connected with the ring 20 and to the circuit of the alarm A which includes the battery B.

It will of course be understood that one of these assemblies is placed on'each wheel and the conductor 23 of each wheel is electrically connected with the alarm circuit as will be shown in Figure 5.

Thus it is seen that as long as the tires are fully inflated the inflatable member 7 will be expanded so that its pressure against the disc 9 will move the stem 10 and its head 14 to a position where said head will be out of contact with the member 13. Thus the circuit to the alarm will be broken. However as soon as one of the tires become partly delated, the member 7 will partly contract and spring 15 will pull the member 9 and its stem 10 towards the valve stem so that the head 14 will engage the contact 13 thus completing the circuit to the alarm or signal A so as to notify the driver or other person in the vehicle that the tire is in need of air.

The alarm or signal A may be placed in any place desired such as on the instrument board or other part of the vehicle.

It is thought from the foregoing description that the advantages and novel features of the invention will be readily understood.

It is to be understood that changes may be made in the construction and in the combination and arrangement of the several parts provided that such changes fall within the no# of the appended claim.

e claim:

In a low pressure si al for tires of motor vehicles a casing having one end provided with a threaded hole, a second casing located in the first casingand having one end open, said end provided with an external flange, a nut threaded in the first casing and clamping the flan e of the second casing against that end of t e first casin which is provided with the threaded hole, t e opposite end of the second casing being closed, a disk bearing against said closed end of the second casing, a contractable spring surrounding the second casing and placed in the first casin and having one end attached to the disk an the other to the nut, a stem connected to the disk and having a head on the free end a hollow plug closing the outer end of the first casin and having a partition therein formed o nonconducting material, a contact ring carried bg' the partition, the stem passing through t e partltion through the center o the ring, whereb when the inner casing contracts the head o the same will be engaged with the rin for closing a circuit.

`testimony whereof we aix' our signaa tures.

JOSEPH G. GEWECKE. MELVIN I. ELLISON. WILLIAM H. MENKING. 

